I too have used a lens pen in the past, but Sunday I watched a TV show where a rep from Swarovski (sp) stated "never use a lens pen. They rapidly take on the grit the brush leaves behind and continue to grind it and newly acquired grit into the lens. Use a soft brush or compressed air first, followed by a soft, clean cloth with liquid lens cleaner to finish." Makes sense to me! From now on, I will use only the brush end of my lens pen and use a liquid cleaner when I get home. Your mileage may vary!